Known for his collection of rarefied estate jewelry, Lee Siegelson of Siegelson (212.?832.?2666, www.siegelson.com) is not concerned with a jewel’s provenance, signature, or commercial appeal; he selects pieces solely for their beauty and rarity. His collection ranges from 19th-century jewelry to pieces from the Art Nouveau and Art Deco eras to contemporary designs from Daniel Brush and Michelle Ong. When he acquires extraordinary gems, he designs his own pieces around them. Among these designs is a new necklace of rubellite, diamond beads, and seed pearls that is valued at more than $450,000. "I have never seen rubellite beads in this cherry color of this size or quality," he says. His estate offerings include a 1937 René Boivin diamond convertible bangle-clip composed of 170 old-mine and European-cut diamonds, and an Art Deco sautoir with diamonds and a 76.11-carat color-change sapphire. Last fall, Siegelson debuted an 18-piece collection of museum-quality designs that he assembled for the 100th anniversary of Neiman Marcus, which has sold ?his collection for the past 15 years. Siegelson’s jewelry also is available at Borsheim’s, Bergdorf Goodman, and other retailers.

Last fall, Van Cleef & Arpels (212.?644.9500, www.vancleef-arpels.com) introduced its L’Atlantide (Atlantis) high-jewelry collection, which features about 100 artistic designs that reference the marine life, legends, and symbols of the fabled underwater city. The Paris house’s approach to jewelry as an artistic and cultural expression recalls the Art Deco period, when jewelry was an integral part of the decorative arts movement.

In 1940, Van Cleef & Arpels created its first jewelry collection inspired by dance, with pieces depicting jeweled ballerinas, Spanish dancers, and fairy clips; the theme has endured for nearly 70 years. Its latest high-jewelry collection, Ballet Précieux (precious ballet), recalls a collaboration between Claude Arpels and choreographer George Balanchine, who produced the Jewels ballet after meeting the jeweler in 1961. Designs in rubies, diamonds, and emeralds re-create the feminine movement of ballerinas in ribbonlike necklaces, small-scale tiara rings, and the house’s signature jeweled ballerina brooches.

Though the Mysterious India high-jewelry collection, which Cartier (800. 227.8437, www.cartier.com) unveiled last fall, may have been inspired by the jewelry house’s designs from the early 1900s, the pieces are obviously contemporary. "There is a fluidness to the jewelry that makes it more fitting for the way women dress and live today," says Pierre Rainero, who holds the title of image, style, and heritage director of Cartier. Like the big, colorful designs from a century ago, the pieces in the new collection are made from cabochon-cut rubies, sapphires, and emeralds. Large amounts of these jewels are combined in elaborate necklaces, chokers, and earrings that drape like fabric against the skin.

Alisa Moussaieff, matriarch of the Moussaieff jewelry house in London (+44.20.7290.1536), broke a world record last October when she paid $7,981,835 for a 6.04-carat internally flawless blue diamond ring at a Sotheby’s Hong Kong auction. "When something so great becomes available, you can’t wait for another chance to buy it. There is no next time," says Moussaieff, who kept tabs on this particular stone for several years before seizing it at the auction. Moussaieff’s passion for rare gems, coupled with her buying power, has made her jewelry collection one of the world’s greatest. In addition to the blue diamond purchase last year, she also acquired a 39-carat Golconda diamond valued around $5 million, and a 20-plus-carat chameleon diamond that changes color, from yellow in daylight to green in the evening. Moussaieff says she is not ready to part with her prized blue diamond just yet, but, she points out, "there is always a market for stones of this caliber."

Fawaz Gruosi, founder of the Swiss jewelry and watch house de Grisogono(212.439.4220, www.degrisogono.com), has an irreverent way with precious gems, often setting the most coveted stones in daring designs. The creative pioneer, who was one of the first to employ black diamonds in high jewelry, set his prized acquisition of last year—a cabochon-cut, 47.71-carat, untreated Burmese ruby—among 372 pale lavender-colored sapphires with a sprinkling of rubies and diamonds. Gruosi’s designs also include an elaborate, bright blue turquoise and emerald necklace and angel-skin coral earrings adorned with fiery red rubies.

For its 10th anniversary on Paris’ Place Vendôme, home to some of the world’s great jewelry houses, Chanel Fine Jewelry(800.550.0005, www.chanel.com) created a collection of 18 all-diamond high-jewelry pieces. Reminiscent of Gabrielle "Coco" Chanel’s one and only diamond jewelry collection, which she unveiled in 1932, the Bijoux de Diamants repeats the French fashion house’s classic motifs—camellias, comets, and stars—in feminine, fluid pieces. Collectively, they comprise 7,800 diamonds weighing more than 500 carats.